CAPE CANAVERAL, Fla. (AP) — Shuttle Discovery’s astronauts have one last spacewalk ahead of them. Late Monday morning, two former schoolteachers — Joseph Acaba and Richard Arnold II — will venture outside the international space station and take another crack at deploying a jammed equipment storage platform.

On Saturday, spacewalkers accidentally inserted a pin upside down on the platform. The catch for the mechanism also proved to be unusually stiff.

This time, Acaba and Arnold will use all their strength to get the platform deployed properly. They will have pry bars and hammers with them, just in case. If all else fails, they will tie the platform down with sturdy tethers to keep it from banging around.

It will be the third and final spacewalk for Discovery’s space station mission.